Miconazole Nitrate Cream
» Miconazole Nitrate Cream contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of miconazole nitrate (C18H14Cl4N2O·HNO3).
Packaging and storage Preserve in collapsible tubes or tight containers, and store at controlled room temperature.
Labeling Cream that is packaged and labeled for use as a vaginal preparation shall be labeled Miconazole Nitrate Vaginal Cream.
USP Reference standards 11
Identification The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
Minimum fill 755: meets the requirements.
Buffer solution Transfer 10 mL of triethylamine to a suitable flask, dilute with 1000 mL of water, adjust with phosphoric acid to a pH of about 2.5, and mix.
Mobile phase Prepare a filtered and degassed mixture of Buffer solution, methanol, acetonitrile, and tetrahydrofuran (8:5:4:3). Make adjustments if necessary (see System Suitablility under Chromatography 621).
Standard preparation Dissolve an accurately weighed quantity of USP Miconazole Nitrate RS and benzoic acid in Mobile phase, and dilute quantitatively, and stepwise if necessary, with Mobile phase to obtain a solution having a known concentration of about 0.28 and 0.02 mg per mL for miconazole nitrate and benzoic acid, respectively.
Assay preparation Transfer an accurately weighed quantity of Cream, equivalent to about 14 mg of miconazole nitrate, to a 50-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix. Sonicate in a water bath at 40 to 45 until the sample is completely dispersed, and mix. Cool the solution to below room temperature, mix, and pass a portion of the solution through a 0.45-µm teflon filter into an HPLC vial.
Chromatographic system (see Chromatography 621) The liquid chromatograph is equipped with a 225-nm detector and 4.6-mm × 25-cm column that contains packing L11. The flow rate is about 1.0 mL per minute. The column temperature is maintained at 45. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the column efficiency for miconazole nitrate peak is not less than 7500 theoretical plates; the tailing factor for miconazole nitrate peak is not more than 2.0; and the relative standard deviation for replicate injections of miconazole nitrate is not more than 2.0%. The resolution between miconazole nitrate and benzoic acid is not less than 13.
Procedure Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of miconazole nitrate (C18H14Cl4N2O·HNO3) in the portion of Cream taken by the formula:
50C(rU / rS)in which C is the concentration, in mg per mL, of USP Miconazole Nitrate RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 3918Pharmacopeial Forum: Volume No. 32(1) Page 123